Many people communicate using multiple devices, phone numbers, and e-mail addresses, among other things. People may have a work phone, a work cell phone, and a personal cell phone. Similarly, people have personal e-mail addresses, work e-mail addresses, personal calendars, work calendars, etc. This means that the user may have to carry multiple devices—e.g., the work cell phone and the personal cell phone—and at the very least, may have to check multiple applications or locations to manage their communications and scheduling.
Currently a cellular phone number, or mobile station international subscriber directory number (MSISDN), is generally only associated with a single subscriber identity module (SIM). As a result, a call to a particular mobile number, for example, causes only the user equipment (UE) with that SIM installed to ring. Thus, if a user forgets a work cell phone at home, they cannot receive or place calls on the work cell phone.